1. Field of the Invention
The present invention relates generally to devices and methods of using a cell, such as a battery.
2. Discussion of Related Art
In the prior art, there are devices for and methods of using cells. For example, U.S. Pat. No. 5,175,485 discloses an apparatus for controlling charging of a storage battery that initially charges the storage battery in a constant current charging mode and then in a constant voltage charging mode when the charging voltage across the storage battery reaches a desired value. Further, U.S. Pat. No. 6,087,810 discloses a battery charger which controls a charging control circuit so as to perform i) constant current charging at a first current value until the voltage value detected by the charging voltage detection circuit reaches a xe2x80x9csecondxe2x80x9d voltage value, ii) constant voltage charging at the second voltage value when the voltage value detected by the charging voltage detection circuit reaches the second voltage value, iii) constant current charging at the first current value again when the current value detected by the charging current detection circuit drops to the second current value, and iv) constant voltage charging at a first voltage value when the voltage value detected by the charging voltage detection circuit reaches the first voltage value, thereby charging the battery.
It is believed the prior art charging methods and devices do not allow a cell to be used as long as the cell could be used. The present invention results in an increase in the number of times a cell may be charged and discharged before that cell no longer provides the energy necessary for the application to which the cell is applied.
The invention may be embodied in a method of using a cell in which the cell is charged to a first voltage and discharged for a discharge time period. After the discharge time period, a voltage of the cell is measured, and compared to a standard voltage. If the measured voltage is greater than the standard voltage, the cell is charged to the first voltage, and if the measured voltage is not greater than the standard voltage, the cell is charged to a second voltage, the second voltage being greater than the first voltage.
The invention may also be embodied in a method of using a cell in which the cell is charged to a charge voltage and discharged for a discharge time period. After the discharge time period, a voltage of the cell is measured, and compared to a first standard voltage and a second standard voltage. If the measured voltage is not greater than the first standard voltage, the cell is charged to a new charge voltage which is greater than the charge voltage. If the measured voltage is greater than the second standard voltage, the cell is charged to a new charge voltage which is less than the charge voltage. If the measured voltage is greater than the first standard voltage, and the measured voltage is not greater than the second standard voltage, then the cell is charged to the charge voltage.